Method and apparatus for shaping and trimming brake drums



June 5, 1923. f

H. w. KRANZ METHOD AND APPARATUS Foa sHAPING AND TRIMMING BRAKE DRUMS 2Sheets-Sheet l June 5, i923.

H. W, KRANZ METHOD AND APPARATUS FOR SHAPING AND TRIMMING BRAKE DRUMSFiled dan. '7, 1921 2 Sheeis-5heet 2 Patented June 5, 1923.

HARRY WM. KRANZ., OF CLEVELAND, OHIO, ASSIGNOR TO THE HYDRAULIC STEEL jCOMPANY, 0F CLEVELAND, OHIO, A CORPORATION OF OHIO.

METHOD .AND APPARATUS FOR SHAPING AND TRIMMING BRAKE DRUMS.

Application filed January 7, 1921. Serial No. 435,655.

To all whom it may concern.:

Be it known that LHARRY l/V. KRANZ, a citizen of the United States,vresiding at Cleveland, in the county of Cuyahoga 'and\ State of Ohio,have invented a certain new and useful Improvement in Methods andApparatus for Shaping vand Trimming Brake Drums, of which the followingis a full, clear, and exact description, reference being had to theaccompanying drawings.

This invention relates to a novel method -and apparatus for truing andshaping and trimming brake drums fashioned of heavy sheet metal. In thefabrication of these drums it frequently happens that they are somewhatnon-circular in shape and also out of plane and in addition to theseimperfections the flange is somewhat wider at some points than others.These imperfecopcrated by means of a shrinking ring 13 having anoutwardly extending member operated upon by a suitable hydrauliccylinder mechanism 15 so that by operating this mechanism the shrinkingring l5 is moved back and forth, Which movement in turn serves toactuate the shrinker blocks 12 and their sections 12a.

The construction of the main frame, ring and shrinker blocks form nopart of the present invention, they being the same as shown anddescribed in the application of George C.'Brainard, filed January 7,v1921, Serial No. 435,654, and consequently a detailed description oft-hese parts will not be necessary at this time.

In addition to the shrinker blocks the main frame and ring also carry amandrel 15 upon which the brake drum 16 is adapttions require correctionbefore 4the brake ed to fit and after the brake drum has been 75 drumcan be used upon an automobile wheel and it is with the idea ofimparting the final correct shape and dimensioning the flange that thepresent method and apparatus has been devised. A With these objects inview the invention consists broadly in arranging a sheet metal brakedrum upon a suitable mandrel or support and subjecting the flangethereof to external radial pressure whereby the said flange is broughtto a true and definite sized circle and at the same time pressure isapplied to the face of the brake drum in order to prevent bulging andcorrect any inaccuracies and preferably simultaneously with the sizingand shaping operations, I provide for trimming off any surplus materialfrom the edges of the flange of the drum. The invention consists also incertain details hereinafter fully described and set forth in theappended claims.

In the drawings forming a part of this specification, Fig. 1 is acentral vertical section partly in elevation; Fig. 2 is a sectionalelevation taken on the line 2`2 of Fig. 1; Fig. 3 is a detail face viewof one of the shrinker block sections with the trimming or shearingknife applied thereto; and Fig. 4 is an enlarged detail sectional viewof the supporting mandrel, shrinker block sections and shearing blades.

In the practical embodiment of my invention I employ a main frame 10upon which is mounted a ring 11 which carries a plurality of segments orblocks 12 which are fitted upon this mandrel the shrinker blocks aremoved radially inward so as to exert the proper external radial pressureupon the flange of the brake drum. At the same time the sizing mandrel17 is forced against the face of the brake drum by means of a hydraulicjack 18 and in connection with each shrinker block section 12a I arrangea trimming knife or blade 18, these parts being arranged-upon the innerface of the shrinker block section and projecting inwardly a sufficientdistance to engage any projecting portion of the brake drum flange andshear the same, as most clearly shown in Figs. 1 and 4; and thisshearing opera- 90 at one and the same time; that is, the flange isbrought to a true circle-and trimmed so as to provide a flange ofuniform width and the face of the drum is brought into a true and properplane. thereby providing a perfectly accurate drum which will avoid thenecessity of subsequent machining.

In connection with the supporting mandrel, knockout pins 19 may beemployed, operated from the hydraulic jack 20 arranged at the rear ofthe main flange.

It will thus be seen that I provide a simple and efficient method andmeans for reshaping and sizing sheet metal brake drums.

Having thus described my invention what I claim is 1. The hereindescribed method of finishing brake drums which consists in arrangingsaid drum upon a suit-able support, subjecting the face and flange ofsaid drum to external pressure, and simultaneously triniming the edgesof said flange.

Q. In a device of the kind described the combination with a supportingmandrel, of radially movable shrinker means surrounding said mandrel.and shearing means carried by said shrinker means.

3. In a device of the kind described the combination with a mandrel, ofshrinker blocks surrounding the same, and means For operating saidblocks and shearing means carried b v said shrinker blocks.

l. In a device of the kind described the combination with a mandrel, ofshrinker blocks surrounding the same, and having inwardly projectingshearing blades and a facing mandrel together with means for moving saidblocks and said mandrel.

In a device of the kind described the combination with a mandrel, ofshrinker blocks surrounding the same, shearing blocks carried by saidshrinker blocks, means for moving said blocks radially, a facing mandreland means for moving the same, and a knock-out device and means formoving the same.

In testimony wherof. l hereunto aiiix my eignature.

HARRY IVM. KRANZ.

